Typical hypertext documents, such as MS Word®, MS Excel®, MS Power Point® or Web pages and other types of displays, such as a window, impose an undue amount of cognitive overhead on readers. For instance, traversing hyperlinks within a source page, determining their relevance, and returning to the source page may disrupt a reader's attention and fragment the reading process. Similarly, within a window a user may have difficulty in determining which links have already been traversed and which one was most recently traversed.
With respect to documents which are displayed, the use of fluid hypertext documents has significantly improved the reading process. Fluid documents use special user interface techniques to provide users with smooth, lightweight and contextual access to additional, supporting information (i.e., annotations) associated with the primary information in a document. This approach involves altering the graphics or typography of a document to show the annotations in the context of the primary information they annotate. When a reader expresses interest in an annotation, space must be made within the document to display the annotation.
Several fluid graphical techniques are used for displaying annotations, such as the fluid interline, margin call-out and overlay methods, in accordance with one or more embodiments disclosed in U.S. Pat. No. 6,230,170 to Zellweger et al., titled “SPATIAL MORPHING OF TEXT TO ACCOMMODATE ANNOTATIONS,” which is incorporated herein by reference in its entirety.
Referring to FIGS. 1-2, the fluid interline technique is shown. A display 10 shows a hypertext fluid document including a Nome information link 12 in source information 14 within passage 16. When a reader wants to know more about Nome, Ak., but does not desire leaving the current page in the document, they may express their interest by moving a cursor over the Nome information link 12 using a mouse, for example, and the interline information 18 is displayed, as shown in FIG. 2. In particular, the top and bottom margins of the passage 16 are moved closer to each other, the line spacing within passage 16 is reduced, and the size of the interline information 18 is gradually scaled up from a small size (e.g., a small, unreadable point on the display 10) to a relatively larger, readable size in between the first portion 20 and the second portion 22.
Referring to FIG. 3, the fluid margin call-out technique is shown. Here, the technique involves gradually drawing a line 24 on the display 10 beginning at the Nome information link 12, moving away from the Nome information link 12 towards the nearest right margin, where the line 24 is then drawn to extend in a vertical direction (e.g., up and/or down) as the margin call-out 26 gradually increases in size the same way the interline information 18 does as discussed above in connection with FIG. 2. As the size increases, drawing the line 24 gently guides a reader's eyes toward the margin call-out 26.
Referring to FIG. 4, the fluid overlay technique is shown. As the overlay 28 increases in size the same way the interline information 18 does as discussed above in connection with FIG. 2, the text in the source information 14 directly underneath the overlay 28 gradually fades to a lighter shade of color to enable the overlay 28 to stand out against the source information 14 as it floats over it.
Fluid documents employing the above-described techniques help readers maintain their reading context in a document. However, fluid documents and other types of displays do not distinguish traversed hyperlinks, annotations, and other areas from those that have not been traversed, for example. Since users often arbitrarily visit pages associated with hyperlinks in a document, it has been noticeably difficult for users to re-orient themselves to the location in a page they were accessing upon their return from the traversed page. More generally, users have trouble re-orienting themselves in a display, such as a window, whenever they interrupt their interaction to work with another application or engage in another task.